Method of manufacturing a metal injection molded part

Abstract

A green machining process comprises receiving a green body made of powder injection molding material and engaging the green body to a clamp pad engaged to a fixture member of a retaining fixture of a machine tool. The clamp pad has a surface hardness smaller than that of the green body. While the green body is supported through the engagement of the clamp pad, the green body is machined using the machine tool to obtain a machined green part. The machining operation may be followed by a debinding and a sintering step.

1 . A method of manufacturing a part, comprising:
 receiving a green body made of powder injection molding material, the powder injection molding material including a binder and a metallic powder material mixed with the binder, the green body having a first surface hardness;   engaging the green body to a clamp pad engaged to a fixture member of a retaining fixture of a machine tool, the clamp pad having a second surface hardness smaller than the first surface hardness;   while supporting the green body through the engagement of the clamp pad, machining the green body using the machine tool to obtain a machined green part; and   debinding and sintering the machined green part.   
     
     
         2 . The method of  claim 1 , further comprising, prior to debinding and sintering, disengaging the clamp pad from the machined green part. 
     
     
         3 . The method of  claim 1 , wherein engaging the green body to the clamp pad maintains the green body in a fixed position during the machining. 
     
     
         4 . The method of  claim 1 , wherein machining the green body includes rotating the green body with the clamp pad and the fixture member. 
     
     
         5 . The method of  claim 1 , further comprising connecting the clamp pad to the fixture member by snuggly engaging first and second complementary locating features with one another, the first locating feature being provided on the clamp pad and the second locating feature being provided on the fixture member. 
     
     
         6 . The method as defined in  claim 1 , further comprising connecting the clamp pad to the fixture member with a fastener. 
     
     
         7 . The method of  claim 1 , further comprising selecting the clamp pad from a set of clamp pads having different configurations of a green-body-engaging surface, the clamp pad being selected based on the green-body-engaging surface thereof and on a surface profile of the green body. 
     
     
         8 . The method of  claim 7 , wherein selecting the clamp pad is based on a configuration of at least one of the fixture member and the machine tool. 
     
     
         9 . The method of  claim 1 , wherein, during the supporting of the green body through the engagement of the clamp pad, the clamp pad has a green-body-engaging surface engaging a surface of the green body, and a fixture-engaging surface engaging the fixture member, the green-body-engaging surface having a first coefficient of friction greater than a second coefficient of friction of the surface of the green body engaging the green-body-engaging surface of the clamp pad. 
     
     
         10 . The method of  claim 9 , wherein, during the supporting of the green body through the engagement of the clamp pad, the clamp pad spreads a load applied by the fixture member over the green-body-engaging surface of the clamp pad. 
     
     
         11 . The method of  claim 9 , wherein, during the supporting of the green body through the engagement of the clamp pad, the clamp pad conforms to the surface of the green body engaging the green-body-engaging surface. 
     
     
         12 . An assembly comprising:
 a green body made of powder injection molding material, the powder injection molding material including a binder and a metallic powder material mixed with the binder, the green body having a first surface hardness;   a retaining fixture of a machine tool, the retaining fixture including a fixture member having a second surface hardness greater than the first surface hardness; and   a clamp pad having a fixture-engaging surface engaged to the fixture member and a green-body-engaging surface engaged to the green body, the fixture-engaging surface having a third surface hardness smaller than the second surface hardness, and the green-body-engaging surface having a fourth surface hardness smaller than the first surface hardness and the second surface hardness.   
     
     
         13 . The assembly of  claim 12 , wherein the retaining fixture is a clamp, and the clamp pad has the fixture-engaging surface parallel to the green-body-engaging surface. 
     
     
         14 . The assembly of  claim 12 , wherein the retaining fixture is a clamp, and the clamp pad has the fixture-engaging surface skewed relative to the green-body-engaging surface. 
     
     
         15 . The assembly of  claim 12 , wherein the retaining fixture is a chuck jaw including a plurality of fixture members, each fixture member of the plurality of fixture members having a corresponding clamp pad connected thereto and engaging the green body. 
     
     
         16 . The assembly of  claim 12 , wherein the fixture member defines an engagement surface embracing a surface profile of the green body on a portion thereof engaged by the green-body-engaging surface of the clamp pad. 
     
     
         17 . The assembly of  claim 12 , wherein the clamp pad conforms to a surface profile of the green body. 
     
     
         18 . The assembly of  claim 12 , wherein the clamp pad comprises a first locating feature and the fixture member comprises a second locating feature complementary shaped for locating the first locating feature upon snuggly engaging the first and second complementary locating features with one another. 
     
     
         19 . The assembly of  claim 12 , further comprising a fastener connecting the clamp pad to the fixture member. 
     
     
         20 . The assembly of  claim 12 , wherein the green-body-engaging surface of the clamp pad has a first coefficient of friction greater than a second coefficient of friction of a surface of the green body engaged to the green-body-engaging surface of the clamp pad.